Image display apparatus

ABSTRACT

A image display apparatus ( 300 ) for displaying a third series ( 104 ) of consecutive output images ( 154 - 158 ) which are based on a first series ( 100 ) of consecutive input images ( 142 - 146 ) and a second series ( 102 ) of consecutive input images ( 148 - 152 ), is arranged to split the images of the first series ( 100 ) of consecutive input images ( 142 - 146 ) into first parts ( 106 - 110 ) and respective second parts ( 118 - 122 ); to split the images of the second series ( 102 ) of consecutive input images ( 148 - 152 ) into third parts ( 112 - 116 ) and respective fourth parts ( 124 - 128 ); and to display a first one ( 158 ) of the output images ( 154 - 158 ) comprising a first block of pixels ( 134 ) corresponding to a first one ( 110 ) of the first parts ( 106 - 110 ) and a second block of pixels ( 140 ) corresponding to a first one ( 128 ) of the fourth parts ( 124 - 128 ).

The invention relates to an image display apparatus comprising:

-   -   first receiving means for receiving a first video signal        representing a first series of consecutive input images;    -   second receiving means for receiving a second video signal        representing a second series of consecutive input images; and    -   a display device for displaying a third series of consecutive        output images which are based on the first series of consecutive        input images and the second series of consecutive input images.

The invention further relates to a method of displaying a third seriesof consecutive output images which are based on a first series ofconsecutive input images and a second series of consecutive inputimages, comprising:

-   -   a first receiving step of receiving a first video signal        representing the first series of consecutive input images; and    -   a second receiving step of receiving a second video signal        representing the second series of consecutive input images.

The invention further relates to a TV comprising such an image displayapparatus.

In video broadcasting, subtitles are employed to convey textualinformation to the viewer. The subtitles accompany an audio/videobroadcast and provide supplemental information to the viewer that maynot be perceivable from the broadcast. Subtitles are frequently used,for example, to aid hearing impaired viewers by displaying the spokenlanguage recorded in the audio soundtrack as written language. Anotherexample, is where subtitles are displayed in different languages thanthe spoken language recorded in the audio soundtrack. In addition,subtitles may be employed to convey important information not related tothe subject matter of the corresponding audio/video broadcast. In thiscase, subtitles may represent late-breaking news, such as: emergencyinformation; sports scores, weather reports or information of the stockexchange. Frequently the information is provided by means of a banner.The textual information moves relative to the display screen of thedisplay apparatus. Typically the direction of the movement is in ahorizontal or vertical direction.

In television broadcasting or video reproduction, such as from a videotape or disk, the subtitles or banners are previously superimposed onthe broadcast and become part of the received images. Hence the displayof the information of the subtitles or banners is linked with thedisplay of the other video content. In many cases this is adisadvantage. It might be that the user is interested in the textualinformation conveyed by the banner or subtitle but not in the othervideo content of the images with which the textual information islinked. E.g. because the user wants to view another channel in themeantime. Some image display apparatus provide a feature which is knownas “picture-in-picture”. In patent specification U.S. Pat. No. 5,130,800is described that multiple pictures from distinct video signals aresimultaneously displayed on a display device of one image displayapparatus. However in that case the dimensions of the pictures from atleast one of the video signals are strongly reduced by means ofsub-sampling. This sub-sampling has a negative influence on thereadability of banners or subtitles.

It is an object of the invention to provide an image display apparatusof the kind described in the opening paragraph on which parts of imagesoriginating from a first series of input images can be displayedsimultaneously with images from a second series of input images whilethe visibility of relevant information conveyed by means of the parts ismaintained.

The object of the invention is achieved in that the image displayapparatus is arranged:

-   -   to split the images of the first series of consecutive input        images into first parts and respective second parts;    -   to split the images of the second series of consecutive input        images into third parts and respective fourth parts; and    -   to display a first one of the output images comprising a first        block of pixels corresponding to a first one of the first parts        and a second block of pixels corresponding to a first one of the        fourth parts.

Relevant parts are selected from the series of input images and combinedto output images to be displayed. This is particularly advantageous inthe case that textual information is conveyed by means of a banner orsubtitle. Then parts of images originating from the first series ofinput images are displayed simultaneously with parts of images from thesecond series of input images while the readability of textualinformation conveyed by means of the parts is maintained.

An embodiment of the image display apparatus according to the inventioncomprises user interface means to provide location information of thefirst parts to control splitting of the images of the series ofconsecutive input images. It is assumed that in a default display modeof the image display apparatus the entire display device is updated on aregular base with images from only one of the series of input image.However if the received input images comprise distinct parts then it isadvantageously to split the images in first parts and second parts andto control the display of the first parts independently of the secondparts. Location information of the first parts relative to the secondparts is required in order to split the received input images. A firstoption is that the user of the image display apparatus provides thisinformation. E.g. by dragging a graphics box or by manipulation of agraphics line being displayed on the display device as a kind ofoverlay. Automatic segmentation of the input images is another option todetermine the location information. Motion estimation is a good basisfor this segmentation. Alternatively the location information isprovided by means of the broadcast.

An embodiment of the image display apparatus according to the inventioncomprises a first memory device for storage of the location information.The location information is relatively constant. By storing the locationinformation it is no longer required to determine or provide thelocation information again. Optionally multiple instances of thelocation information are stored as a presetting for the variousbroadcasting channels. In that case a user of the image displayapparatus might start the required display mode, i.e. split displaymode, with one push of a button of the remote control. Optionally theimage display apparatus automatically switches from a default displaymode in which the entire display device is updated on a regular baseinto the split display mode. This switching might be triggered by a“banner-event”, i.e. the presence of a banner is detected.

An embodiment of the image display apparatus according to the inventioncomprises scaling means to scale the first parts. Suppose that in adefault splitting both images of the first series and the images of thesecond series are split on basis of the same location information. E.g.at ¼ of the height of the images. That means that the first partscorrespond with ¾ of the respective input images of the first series,the second parts correspond with at ¼ of the respective input images ofthe first series, the third parts correspond with ¾ of the respectiveinput images of the second series, and the fourth parts correspond withat ¼ of the respective input images of second first series. In that casea first one of the first parts is directly combined with a first one ofthe fourth parts. However if the splitting for the images of thedistinct series is not on basis of the same location information then ascaling can be applied to a group of parts. E.g. if the splitting of theimages of the second series is at ⅙ of the height and the splitting ofthe images of the second series is at ¼ of the height then a verticalscaling of {fraction (3/2)} of the fourth parts should be applied. Thisresults in output images comprising copies of the first parts andvertically scaled versions of the fourth parts. Scaling of both fourthand first parts is an alternative approach.

An embodiment of the image display apparatus according to the inventioncomprises processing means to assign a new color value to a first pixelof the second block of pixels on basis of an original color value of thefirst pixel. A color adaptation of the pixels of one of the groups ofblocks is advantageous if it is required to inform the viewer of theimage display apparatus about the display mode: split display mode. Inother words, the viewer can easily observe that the output images arebased on distinct series of input images. Besides that, the readabilityof the information can be enhanced by means of color adaptation.Alternatively the luminance of the pixels of one of the groups of blocksis adjusted independent from the pixels of the other group of blocks. Ina preferred embodiment a LUT (Look-Up-Table) is applied for the coloradaptation.

It is a further object of the invention to provide a method of the kinddescribed in the opening paragraph with which parts of imagesoriginating from a first series of input images can be displayedsimultaneously with images from a second series of input images whilethe visibility of relevant information conveyed by means of the parts ismaintained.

This object of the invention is achieved in that the method comprises:

-   -   a first splitting step of splitting the images of the first        series of consecutive input images into first parts and        respective second parts;    -   a second splitting step of splitting the images of the second        series of consecutive input images into third parts and        respective fourth parts; and    -   a display step of displaying a first one of the output images        comprising a first block of pixels corresponding to a first one        of the first parts and a second block of pixels corresponding to        a first one of the fourth parts.

Modifications of the image display apparatus and variations thereof maycorrespond to modifications and variations thereof of the methoddescribed.

These and other aspects of the image display apparatus, of the TV and ofthe method according to the invention will become apparent from and willbe elucidated with respect to the implementations and embodimentsdescribed hereinafter and with reference to the accompanying drawings,wherein:

FIG. 1 schematically shows two series of input images and a series ofoutput images according to the invention;

FIG. 2 schematically shows an embodiment of the user interface for thecontrol of the splitting;

FIG. 3 schematically shows an embodiment of the image display apparatus;

FIG. 4A and 4B schematically show examples of repositioning parts;

FIG. 5A and 5B schematically show examples of scaling parts; and

FIG. 6 schematically show an example of color adaptation.

Corresponding reference numerals have same or like meaning in all of theFIGS.

FIG. 1 schematically shows two series 100, 102 of input images 142-152and a series 104 of output images 154-158 according to the invention.The images 142-146 represent a portion of a sport game. The images148-152 represent a portion of a car program. Besides that, textualinformation is provided in the lower parts 124-128 of the images148-152. A first one 158 of the consecutive output images 154-158comprises a first part 134 which corresponds to a first block ofconnected pixels 110 of a first one 146 of the first series ofconsecutive input images 142-146, and a second part 140 whichcorresponds to a second block of connected pixels 128 of the first one152 of the second series of consecutive input images 148-152. A secondone 156 of the consecutive output images 154-158 comprises a first part132 which corresponds to a third block of connected pixels 108 of asecond one 144 of the first series of consecutive input images 142-146,and a fourth part 138 which corresponds to a fourth block of connectedpixels 126 of the second one 150 of the second series of consecutiveinput images 148-152. Hence, the output images 154-158 comprise blocksof pixels 130-134 which correspond to the first parts 106-110 of therespective input images 142-146 of the first series and comprise blocksof pixels 136-140 which correspond to the fourth parts 124-128 of therespective input images 148-152 of the second series of output images.

FIG. 2 schematically shows an embodiment of the user interface for thecontrol of the splitting between a first part 112 and a second part 124of the input image 148. On the display device 306 a graphics line 200 isdrawn as an overlay of the input image 148. The user of the imagedisplay apparatus 300 can adapt the position of the line by means ofpushing a plus or minus button of the remote control of the imagedisplay apparatus 300.

Such manipulation of the display can be achieved using the facilities ofthe OSD (On Screen Display) features of the display apparatus 300 and orother graphics features of the display apparatus 300. The position ofthe line 200, corresponds to the location information which is requiredto split the images 148-152 of the series 102 of input images in firstparts 112-116 and second parts 124-128. Optionally the position of theline 200 is stored in a memory device. Preferably multiple instances arestored, e.g. a first position for channel 1, a second position forchannel 2, etcetera.

FIG. 3 schematically shows an embodiment of the image display apparatus300 comprising:

-   -   a first receiving means 301 for receiving a signal representing        input images 142-146 of the first series 100 of consecutive        input images. The signal may be a broadcast signal received via        an antenna or cable but may also be a signal from a storage        device like a VCR (Video Cassette Recorder) or Digital Versatile        Disk (DVD). The signal is provided at the input connector 308.        The first receiving means is arranged to be tuned to a first        predetermined frequency band to extract the input images 142-146        from the provided signal.    -   a second receiving means 302 for receiving a signal representing        input images 148-152 of the second series 102 of consecutive        input images. The second receiving means is arranged to be tuned        to a second predetermined frequency band to extract the input        images 148-152 from the provided signal.    -   processing means 304 for making the output images 154-158 on        basis of the input images 142-152. The processing means 304        comprises memory devices for buffering incoming data, i.e. pixel        values of input images. The pixel values which are required to        make an output image 154-158 have to be read from the memory        device in the appropriate order.    -   display means for displaying the output images 110-114. This        display means is optional. The functionality can also deployed        by making use of a e.g. Set-top box. In that case the displaying        is done by a Television and other parts of the processing by        means the Set-top box.

FIG. 4A schematically shows an example of repositioning a part 128. FIG.4A shows that output image 406 comprises a first block of pixels 410located at the lower side of the output image 406. This first block ofpixels 410 corresponds to a first part 404 which is located in the lowerpart of a first image 142 of the first series 100 of input images.Output image 406 also comprises a second block of pixels 408 located atthe upper side of the output image 406. This second block of pixels 408corresponds to a fourth part 128 which is located in the lower part of afirst image 152 of the second series 102 of input images. Thisrepositioning can easily be done by means of a memory device.

FIG. 4B schematically shows an example of repositioning parts 128 and106. FIG. 4B shows that output image 414 comprises a first block ofpixels 412 located at the lower side of the output image 414. This firstblock of pixels 412 corresponds to a first part 106 which is located inthe upper part of a first image 142 of the first series 100 of inputimages. Output image 414 also comprises a second block of pixels 408located at the upper side of the output image 414. This second block ofpixels 408 corresponds to a fourth part 128 which is located in thelower part of a first image 152 of the second series 102 of inputimages.

FIG. 5A schematically shows an examples of scaling a part 128. FIG. 5Ashows that output image 506 comprises a first block of pixels 510located at the lower side of the output image 506. This first block ofpixels 510 corresponds to a first part 504 which is located in the lowerpart of a first image 142 of the first series 100 of input images.Output image 506 also comprises a second block of pixels 508 located atthe upper side of the output image 506. This second block of pixels 508corresponds to a vertically scaled fourth part 128 which is located inthe lower part of a first image 152 of the second series 102 of inputimages. The fourth part 128 is enlarged.

FIG. 5B schematically shows an examples of scaling parts 128 and 516.FIG. 5A shows that output image 512 comprises a first block of pixels518 located at the lower side of the output image 512. This first blockof pixels 518 corresponds to a vertically scaled first part 516 which islocated in the lower part of a first image 142 of the first series 100of input images. Output image 512 also comprises a second block ofpixels 508 located at the upper side of the output image 512. Thissecond block of pixels 508 corresponds to a vertically scaled fourthpart 128 which is located in the lower part of a first image 152 of thesecond series 102 of input images. The fourth part 128 is enlarged whilethe first part 516 is reduced.

In the case that viewer sees an interesting subject in either the lowerside or the upper side of the output image, the user can switch to thecorresponding channel of interest by a minimum of interaction. This willbe illustrated by means of some examples. Assume the case that a vieweris looking at a news channel with the banner from MTV (Music). Theviewer is waiting for a interesting song on the banner from MTV, but iswatching the news.

The viewer will wish to switch rapidly from the viewed channel to thechannel with the banner. This will need to be one button push away andnot via channel zapper, which could take you through a number ofchannels. Similar to the example above but slight more advanced. In thiscase the viewer is waiting for a song on the banner, but does not wishto move to view the MTV channel, but wish to listen to the sound fromthat channel. This could also be one button mode. Or the viewer may wishto switch from split channel-banner viewing of a channel to PIP (picturein picture) mode with both channels on display.

FIG. 6 schematically show an example of color adaptation. FIG. 6 showsthat output image 602 comprises a first block of pixels 410 located atthe lower side of the output image 406. This first block of pixels 410corresponds to a first part 404 of a first image 142 of the first series100 of input images. Output image 406 also comprises a second block ofpixels 604 located at the upper side of the output image 406. Thissecond block of pixels 604 is derived from a fourth part 128 of a firstimage 152 of the second series 102 of input images. The pixel values ofthe second block of pixels 604 are determined by means of a LUToperation with the pixel values of the fourth part 128 as inputoperands. Color adaptation might also mean rendering of the banner ingrey-scale or black and white.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention and that those skilled in the art willbe able to design alternative embodiments without departing from thescope of the appended claims. In the claims, any reference signs placedbetween parentheses shall not be constructed as limiting the claim. Theword ‘comprising’ does not exclude the presence of elements or steps notlisted in a claim. The word “a” or “an” preceding an element does notexclude the presence of a plurality of such elements. The invention canbe implemented by means of hardware comprising several distinct elementsand by means of a suitable programmed computer. In the unit claimsenumerating several means, several of these means can be embodied by oneand the same item of hardware.

1. An image display apparatus (300) comprising: first receiving means(302) for receiving a first video signal representing a first series(100) of consecutive input images (142-146); second receiving means(301) for receiving a second video signal representing a second series(102) of consecutive input images (148-152); and a display device (306)for displaying a third series (104) of consecutive output images(154-158) which are based on the first series (100) of consecutive inputimages (142-146) and the second series (102) of consecutive input images(148-152), characterized in that the image display apparatus (300) isarranged: to split the images (142-146) of the first series (100) ofconsecutive input images (142-146) into first parts (106-110) andrespective second parts (118-122); to split the images (148-152) of thesecond series (102) of consecutive input images (148-152) into thirdparts (112-116) and respective fourth parts (124-128); and to display afirst one (158) of the output images (154-158) comprising a first blockof pixels (134) corresponding to a first one (110) of the first parts(106-110) and a second block of pixels (140) corresponding to a firstone (128) of the fourth parts (124-128).
 2. An image display apparatus(300) as claimed in claim 1, characterized in that the fourth parts(124-128) correspond to respective portions of a banner.
 3. An imagedisplay apparatus (300) as claimed in claim 1, characterized in that thefourth parts (124-128) correspond to a subtitle.
 4. An image displayapparatus (300) as claimed in claim 1, characterized in comprising userinterface means (200) to provide location information of the fourthparts (124-128) to control splitting of the images of the second series(102) of consecutive input images (148-152).
 5. An image displayapparatus (300) as claimed in claim 4, characterized in comprising afirst memory device for storage of the location information.
 6. An imagedisplay apparatus (300) as claimed in claim 1, characterized incomprising scaling means to scale the first parts (106-110).
 7. An imagedisplay apparatus (300) as claimed in claim 1, characterized incomprising processing means to assign a new color value to a first pixelof the second block of pixels (604) on basis of an original color valueof the first pixel.
 8. A method of displaying a third series (104) ofconsecutive output images (154-158) which are based on a first series(100) of consecutive input images (142-146) and a second series (102) ofconsecutive input images (148-152), comprising: a first receiving stepof receiving a first video signal representing the first series (100) ofconsecutive input images (142-146); and a second receiving step ofreceiving a second video signal representing the second series (102) ofconsecutive input images (148-152), characterized in that the methodcomprises: a first splitting step of splitting the images (142-146) ofthe first series (100) of consecutive input images (142-146) into firstparts (106-110) and respective second parts (118-122); a secondsplitting step of splitting the images (148-152) of the second series(102) of consecutive input images (148-152) into third parts (112-116)and respective fourth parts (124-128); and a display step of displayinga first one (158) of the output images (154-158) comprising a firstblock of pixels (134) corresponding to a first one (110) of the firstparts (106-110) and a second block of pixels (140) corresponding to afirst one (128) of the fourth parts (124-128).
 9. TV comprising an imagedisplay apparatus (300) according to claim 1.